I agree, I take my client's representation to me at face value and I don't cross that line either. If a client tries to involve me in a tax avoidance scheme or fraud, I would just resign and move on. Also, I don't think any of the CPAs I work with would tell me "oh by the way, Dr. Payne is giving his kids a salary so they can defer but they they never actually work for him". Even if that was the case, why volunteer that information in the first place?